The present application is based on and claims priority to Japanese Patent Application No. 11-170731, which was filed on Jun. 17, 1999, the entire contents of which are hereby expressly incorporated by reference. The entire contents of Japanese Patent Application No. 11-75968, which was filed on Mar. 19, 1999, are also hereby expressly incorporated by reference.
1. Field of the Invention
The present invention generally relates to a control system for a personal watercraft. More particularly, the present invention relates to a emergency shut-off system for a personal watercraft.
2. Description of Related Art
As personal watercraft have become popular, they have become increasingly fast. Today, personal watercrafts are capable of speeds greater than 60 mph. To attain such speeds, personal watercrafts are driven by high power output motors.
Typically, two-cycle engines are used in personal watercraft because two-cycle engines have a fairly high power to weight ratio. One disadvantage of two-cycle engines, however, is that they produce relatively high emissions. In particular, large amounts of carbon monoxide and hydrocarbons are produced during operation of the engine. When steps are taken to reduce these emissions, other undesirable consequences typically result, such as an increase in the weight of the engine, the cost of manufacture, and/or the reduction of power.
It has been suggested that four-cycle engines replace two-cycle engines in personal watercraft. Four-cycle engines typically produce less hydrocarbon emissions than two-cycle engines while still producing a relatively high power output. However, adapting four-cycle engines for use in personal watercraft has its own engineering and technical challenges.
As is known, vapor separators are used to separate fuel vapors from a fuel supply. The vapor separator contains a small reservoir in which fuel is collected and allowed to settle to some degree. The fuel is drawn from the vapor separator and supplied to a high pressure fuel supply system, which often contains a number of fuel injectors in more recent years.
In some applications, the vapor separator is manufactured of aluminum. As is known, water corrosion is a concern with aluminum components. Thus, it is desired that the vapor separator be protected from significant water contact. At the same time, aluminum is a very efficient heat conductor. Because the temperature of the fuel should not be significantly elevated within the vapor separator, placement of the vapor separator becomes a significant concern. Specifically, the vapor separator desirably is spaced apart from high temperature components.
Accordingly, one aspect of the present invention involves a personal watercraft comprising a hull with an engine compartment being defined within said hull. An engine is mounted within said engine compartment and an air intake chamber is positioned to a side of said engine. At least one intake pipe extends between said intake chamber and said engine and a vapor separator is disposed between said intake chamber and said engine.
Another aspect of the present invention involves a personal watercraft comprising a hull carrying a longitudinally-extending straddle-type seat. An engine compartment is disposed generally beneath said seat and an engine is mounted in said engine compartment. The engine comprises a crankcase, a cylinder body and a cylinder head. A crankshaft is mounted for rotation within said crankcase. A first generally vertical plane is defined at an outermost surface of said crankcase and a reference plane extends generally parallel to said first plane and extends through said crankshaft. A vapor separator is positioned between said first plane and said reference plane.